Measurements were made of the dipolar spin lattice relaxation time of 1H in amorphous hydrogenated material in order monitor the local motion of H. The variation in relaxation time with doping level revealed a trend which was similar to the changes in H diffusivity that were measured by means of secondary ion mass spectroscopy. The temperature variation of the dipolar spin lattice relaxation time indicated that, if the local motion was thermally activated, the activation energies were at least an order of magnitude lower than those measured using secondary ion mass spectrometry. The so-called diffusion coefficients for local H motion that were deduced from the relaxation time measurements were many orders of magnitude higher than the diffusion constants that were deduced from secondary ion mass spectrometric data. It was noted that the relaxation time measurements were performed at the ms scale, while the secondary ion mass spectrometric measurements were performed over many hours. A phenomenological model was developed which provided a reasonable rationalization of these 2 types of data.

Hydrogen Motion in Hydrogenated Amorphous Silicon (a-Si:H). P.Hari, P.C.Taylor, R.A.Street: Journal of Non-Crystalline Solids, 1996, 198-200[1], 52-5